https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78661
--- Comment #7 from janus at gcc dot gnu.org ---
So, here is a corrected test for the polymorphic case:
MODULE m
IMPLICIT NONE
TYPE :: t
CHARACTER :: c
CONTAINS
PROCEDURE :: write_formatted
GENERIC :: WRITE(FORMATTED) => write_formatted
PROCEDURE :: read_formatted
GENERIC :: READ(FORMATTED) => read_formatted
END TYPE
CONTAINS
SUBROUTINE write_formatted(dtv, unit, iotype, v_list, iostat, iomsg)
CLASS(t), INTENT(IN) :: dtv
INTEGER, INTENT(IN) :: unit
CHARACTER(*), INTENT(IN) :: iotype
INTEGER, INTENT(IN) :: v_list(:)
INTEGER, INTENT(OUT) :: iostat
CHARACTER(*), INTENT(INOUT) :: iomsg
WRITE (unit, "(A)", IOSTAT=iostat, IOMSG=iomsg) dtv%c
END SUBROUTINE
SUBROUTINE read_formatted(dtv, unit, iotype, v_list, iostat, iomsg)
CLASS(t), INTENT(INOUT) :: dtv
INTEGER, INTENT(IN) :: unit
CHARACTER(*), INTENT(IN) :: iotype
INTEGER, INTENT(IN) :: v_list(:)
INTEGER, INTENT(OUT) :: iostat
CHARACTER(*), INTENT(INOUT) :: iomsg
READ (unit, "(A)", IOSTAT=iostat, IOMSG=iomsg) dtv%c
END SUBROUTINE read_formatted
END MODULE
PROGRAM p
USE m
IMPLICIT NONE
class(t), allocatable :: x
NAMELIST /nml/ x
x = t('a')
WRITE (*, nml)
END
It currently prints (with my patch from comment 4, but probably also without):
&NML
X=
/
Apparently 'write_formatted' is not called. The dump for the non-poly version
from comment 0/3 shows:
_gfortran_st_set_nml_dtio_var (&dt_parm.3, x, &"x"[1]{lb: 1 sz: 1}, 0, 0, 40,
write_formatted, (void *) &__vtab_m_T);
But for the polymorphic version it has:
_gfortran_st_set_nml_dtio_var (&dt_parm.3, &x, &"x"[1]{lb: 1 sz: 1}, 0, 0, 56,
0B, 0B);
Neither the DTIO procedure nor the vtab is called. The DTIO procedure we need
here is "x._vptr->write_formatted".
Btw why do we actually pass the vtab in the first case?
